In industrial and construction machinery, hydraulic cylinders as frequently used to control the movement and operation of machine components. Typically, the cylinder tube end of the hydraulic cylinder is connected to the machinery frame, and the distal end of the telescoping cylinder rod is connected to the machine component. In this arrangement, when the machine component is in a non-operating mode, the cylinder rod is normally fully retracted in the cylinder tube. However, due to hydraulic fluid leakage in the valve, seals, lines, fittings or other places, the weight of the machine component, or other forces, may cause the cylinder rod to undesirably extend from the cylinder tube when the hydraulic cylinder is not actuated.
Prior art devices have attempted to latch or restrain the cylinder rod in the retracted position when a machine component attached thereto is not being operated, but such devices have either required a machine operator to leave from his machine station or seat to engage a latch or linkage to lock the cylinder rod in the retracted position, or have required separate latch or linkage parts to be attached to the frame of the overall machine.
There are several disadvantages of a device which requires a latching or linkage part to be attached to the machine frame. One disadvantage is that the latching part attached to the machine may come out of alignment with its mating part attached to the cylinder rod or cylinder tube. Another disadvantage is that the design of such a latching device requires that part of the machine frame must be located near the machine component or hydraulic cylinder being latched, in order for the latching part attached to the frame to mate with the latching part attached to the machine component or cylinder, which may require additional design considerations.